US3355621A - System for regulating focus current and voltage in a television camera - Google Patents

System for regulating focus current and voltage in a television camera Download PDF

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Publication number
US3355621A
US3355621A US441186A US44118665A US3355621A US 3355621 A US3355621 A US 3355621A US 441186 A US441186 A US 441186A US 44118665 A US44118665 A US 44118665A US 3355621 A US3355621 A US 3355621A
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United States
Prior art keywords
voltage
current
electrode
sample
circuit
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Expired - Lifetime
Application number
US441186A
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English (en)
Inventor
William J Cosgrove
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
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RCA Corp
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Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Priority to US441186A priority Critical patent/US3355621A/en
Priority to GB8050/66A priority patent/GB1117293A/en
Priority to DE19661563633 priority patent/DE1563633C3/de
Priority to SE3615/66A priority patent/SE325049B/xx
Priority to NL666603564A priority patent/NL148768B/xx
Application granted granted Critical
Publication of US3355621A publication Critical patent/US3355621A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/40—Circuit details for pick-up tubes

Definitions

  • the scanning beam focus is effected under the joint control of an electrostatic field produced from within the tube and of an electromagnetic field produced from outside of the tube.
  • the electrostatic field producing means is energized by voltage and the electromagnetic field producing means is energized by current.
  • the beam focussing systems is subjected to heat generated within the camera. Any change in the temperature of such apparatus tends to change either or both of the current and voltage supplied to the focussing systems. It is desirable that both focussing current and voltage be maintained as constant as possible but it is also equally desirable that any changes in the current, for example, be accompanied by corresponding changes of the voltage.
  • a voltage representative of the current to be regulated is compared with and made substantially identical to a stable reference voltage.
  • a sample of the voltage to be regulated then is compared with and made substantially identical to the current representative voltage.
  • the pickup tube 1 is illustrated as being of the well known image orthicon type which includes such electrodes as an electron gun and multiplier apparatus 2, an electrostatic beam focussing electrode 3 internally of the tube. Externally, the pickup tube is provided with auxiliary apparatus such as an electromagnetic focussing coil 4 and a beam deflection coil 5.
  • the electrostatic focussing electrode 3, forming part of an electron-optical beam focussing lens, is provided with a suitable operating potential derived from a potentiometer 6 which forms part of a voltage divider 7 also including resistors 8 and 9 connected in the emitter electrode circuit of a voltage regulating transistor 11, the collector electrode of which is connected to a voltage source E
  • Operating current is provided for the focussing coil 4 from the source E by a circuit connected to the collector electrode of a current regulating transistor 12 in the emitter electrode circuit of which is connected a voltage divider 13 comprising resistors 14 and 15.
  • the current regulating transistor 12 preferably is of the type having a large transmission ratio of collector current to base current.
  • the emitter current therefore, is
  • the voltage sample taken at the point 16 of the voltage divider 13 is compared with a stable reference voltage relative to ground present at the ungrounded terminal of a zener diode 17. This comparison is made by a differential amplifier 18 comprising transistors 19 and 21.
  • the stable reference voltage is applied to the base of transistor 19 and the sample voltage is applied to the base of transistor 21.
  • the collector and emitter electrode circuits of these transistors are identical so that any difference between the respective voltages applied to the base electrodes of these transistors is effective to produce an error signal at an output terminal 22 connected to the collector electrode of transistor 21.
  • This error signal is applied through an amplifier 23 to the base electrode of the current regulating transistor 12 and is effective to suitably alter the collector-to-emitter electrode current flow in this transistor so as to produce a sample voltage at the point 16 of the voltage divider 13 which is substantially equal to the reference voltage across the zener diode 17. In this way, the current in the focussing coil 4 is regulated and the voltage drop across the voltage divider 13 is substantially stabilized.
  • the voltage at the point 24 of the voltage divider 7 is representative of the voltage applied to the focus electrode 3 of the pickup tube 1.
  • This sample voltage is compared with the voltage drop across the voltage divider 13 by a second differential amplifier 25 which is similar in character to the differential amplifier 18.
  • the essentially stable reference voltage applied to the base of transistor 26 is representative of the current in the focus coil 4 and is used as a comparison reference for the sample voltage at the point 24 of the voltage divider 7 which is applied to the base of transistor 27. Any difference in these two voltages produces an error signal at an output terminal 28 connected to the collector electrode of the transistor 27. This error voltage is then applied through an amplifier 29 to the base electrode of the voltage regulating transistor 11.
  • the collector-to-emitter current flow in this transistor is altered suitably to produce a voltage derived from the potentiometer 6 and applied to the electrostatic focus electrode 3 which maintains a predetermined relationship with the current through the electromagnetic focus coil 4. It has been found that substantially perfect tracking between the electrostatic focus voltage and the electromagnetic focus current can be obtained by suitably proportioning the values of resistors 8 and 9 and by the adjustment of potentiometer 6 of the voltage divider 7.
  • a system for regulating current in one circuit and voltage in a related circuit comprising:
  • means including a current regulating device for supplying current to said one circuit
  • a voltage regulating device for supplying voltage to said related circuit; means coupled to said voltage regulating device to produce a second sample voltage representative of the voltage supplied to said related circuit; means responsive to said second sample voltage and to a voltage representative of the current supplied to said one circuit to produce a second error signal representative of any difference between said second sample and said current representative voltages; and means responsive to said second error signal to so control said voltage regulating device as to maintain the voltage in said related circuit substantially constant and in fixed relation to the current in said one circuit.
  • a current regulating transistor having a current control electrode; means including said current regulating transistor for supplying energizing current to said focus coil; means connected to said current regulating transistor to produce a current indicating voltage representative of current fiow in said focus coil;
  • a first comparator responsive to a first sample of said current indicating voltage and to said reference voltage to produce a first error signal representative of any difference between said first sample and said reference voltage
  • means including said voltage regulating transistor for developing and supplying an energizing voltage to said focus electrode;
  • a second comparator responsive to a second sample taken from said voltage developing means and to said current indicating voltage to produce a second error signal representative of any difference between said second sample and said current indicating voltage;
  • a system for regulating focus current and voltage comprising:
  • a current regulating transistor having base. emitter and collector electrodes;
  • means including the collector-to-emitter electrode circuit of said current regulating transistor for supplying energizing current to said focus coil;
  • a first comparator responsive to a first sample of said current indicating voltage and to said reference voltage to produce a first error signal representative of any difference between said first sample and said reference voltage
  • a voltage regulating transistor having base, emitter and collector electrodes
  • means including voltage developing apparatus connected in the collector-to-emitter circuit of said voltage regulating trunsisior emitter electrode for supplying an energizing voltage to said focus electrode;
  • a second comparator responsive to a second sample taken from said energizing voltage supplying means and to said current indicating voltage to produce a second error signal representative of any difference between said second sample and said current indicating voltage;
  • a system for regulating focus current and voltage comprising:
  • a current regulating transistor having base, emitter and collector electrodes
  • a first comparator responsive to a first sample of said current indicating voltage and to said reference voltage to produce a first error signal representative of any difference between said first sample and said reference voltage
  • a voltage regulating transistor having base, emitter and collector electrodes
  • a second comparator responsive to a second sample taken from said voltage developing means and to said current indicating voltage to produce a second error signal representative of any difference between said second sample and said current indicating voltage;
  • a system for regulating focus current and voltage comprising:
  • a current regulating transistor having base, emitter and collector electrodes
  • a first comparator comprising a first pair of voltage comparison transistors, each having base, emitter and collector electrodes;
  • a voltage regulating transistor having base, emitter and collector electrodes
  • a second comparator comprising a second pair of voltage comparison transistors, each having base, emitter and collector electrodes;
  • a system for regulating focus current and voltage comprising:
  • a current regulating transistor having base, emitter and collector electrodes
  • a first comparator comprising a first pair of voltage comparison transistors, each having base, emitter and collector electrodes;
  • a voltage regulating transistor having base, emitter and collector electrodes
  • a second comparator comprising a second pair of voltage comparison transistors, each having base, emitter and collector electrodes;
  • a system for regulating focus current and voltage comprising:
  • a current regulating transistor having base, emitter and collector electrodes
  • a first differential amplifier comprising a first pair of voltage comparison transistors, each having base, emitter and collector electrodes;
  • means including a first amplifier for impressing said first error voltage upon the base electrode of said current regulating transistor, thereby to so control conductivity of said current regulating transistor as to maintain the current in said focus coil and the voltage across said first voltage divider substantially constant;
  • a voltage regulating transistor having base, emitter and collector electrodes
  • a second differential amplifier comprising a second pair of voltage comparison transistors, each having base, emitter and collector electrodes;

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Continuous-Control Power Sources That Use Transistors (AREA)
  • Details Of Television Scanning (AREA)
  • Electron Sources, Ion Sources (AREA)
US441186A 1965-03-19 1965-03-19 System for regulating focus current and voltage in a television camera Expired - Lifetime US3355621A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US441186A US3355621A (en) 1965-03-19 1965-03-19 System for regulating focus current and voltage in a television camera
GB8050/66A GB1117293A (en) 1965-03-19 1966-02-23 Current and voltage regulating system
DE19661563633 DE1563633C3 (de) 1965-03-19 1966-03-18 Stromversorgungsschaltung
SE3615/66A SE325049B (ja) 1965-03-19 1966-03-18
NL666603564A NL148768B (nl) 1965-03-19 1966-03-18 Inrichting voor het focusseren van een elektronenstraal in een televisiecamerabuis.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US441186A US3355621A (en) 1965-03-19 1965-03-19 System for regulating focus current and voltage in a television camera

Publications (1)

Publication Number Publication Date
US3355621A true US3355621A (en) 1967-11-28

Family

ID=23751876

Family Applications (1)

Application Number Title Priority Date Filing Date
US441186A Expired - Lifetime US3355621A (en) 1965-03-19 1965-03-19 System for regulating focus current and voltage in a television camera

Country Status (4)

Country Link
US (1) US3355621A (ja)
GB (1) GB1117293A (ja)
NL (1) NL148768B (ja)
SE (1) SE325049B (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3471640A (en) * 1967-04-26 1969-10-07 Hellyer Arthur L Temperature compensated electron beam focus control system
US3879637A (en) * 1972-03-22 1975-04-22 Us Navy Television camera
US4361784A (en) * 1979-11-23 1982-11-30 Rca Corporation System for coupling the focus current to the focus voltage of a camera tube

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939042A (en) * 1958-01-16 1960-05-31 Thompson Ramo Wooldridge Inc Automatic focusing circuit
US2942148A (en) * 1958-07-10 1960-06-21 Thompson Ramo Wooldridge Inc Temperature compensated camera tube target supply
US3165675A (en) * 1960-09-29 1965-01-12 First Pennsylvania Banking And Apparatus for producing a magnetic field
US3218468A (en) * 1965-11-16 Transistor circuit capable of deliver- ing, independently of the load, an output current proportional to the difference between two voltages

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3218468A (en) * 1965-11-16 Transistor circuit capable of deliver- ing, independently of the load, an output current proportional to the difference between two voltages
US2939042A (en) * 1958-01-16 1960-05-31 Thompson Ramo Wooldridge Inc Automatic focusing circuit
US2942148A (en) * 1958-07-10 1960-06-21 Thompson Ramo Wooldridge Inc Temperature compensated camera tube target supply
US3165675A (en) * 1960-09-29 1965-01-12 First Pennsylvania Banking And Apparatus for producing a magnetic field

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3471640A (en) * 1967-04-26 1969-10-07 Hellyer Arthur L Temperature compensated electron beam focus control system
US3879637A (en) * 1972-03-22 1975-04-22 Us Navy Television camera
US4361784A (en) * 1979-11-23 1982-11-30 Rca Corporation System for coupling the focus current to the focus voltage of a camera tube

Also Published As

Publication number Publication date
SE325049B (ja) 1970-06-22
NL148768B (nl) 1976-02-16
DE1563633B2 (de) 1973-03-29
DE1563633A1 (de) 1970-05-27
NL6603564A (ja) 1966-09-20
GB1117293A (en) 1968-06-19

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